Semiconductor device

Abstract

There is provided a semiconductor device comprising, at least one SRAM cell, wherein the SRAM cell includes a pull-up transistor, a pull-down transistor, and a pass-gate transistor, and an inversion-layer thickness (Tinv) of a gate stack of the pass-gate transistor is different from Tinv of a gate stack of the pull-up transistor and Tinv of a gate stack of the pull-down transistor.

What is claimed is: 
     
       1. A semiconductor device comprising:
 at least one SRAM cell, 
 wherein the SRAM cell includes a pull-up transistor, a pull-down transistor, and a pass-gate transistor, and 
 an inversion-layer thickness (Tinv) of a gate stack of the pass-gate transistor is different from a Tinv of a gate stack of the pull-up transistor and Tinv of a gate stack of the pull-down transistor, and 
 wherein a nitrogen concentration of a gate insulating film of the pass-gate transistor is different from a nitrogen concentration of a gate insulating film of the pull-up transistor and a nitrogen concentration of a gate insulating film of the pull-down transistor. 
 
     
     
       2. The semiconductor device of  claim 1 , wherein the gate insulating film of each of the transistors comprises a high-k material. 
     
     
       3. The semiconductor device of  claim 1 , wherein an interface film is formed between a substrate and the gate insulating film of each of the transistors, and
 a nitrogen concentration of the interface film of the pass-gate transistor is different from a nitrogen concentration of the interface film of the pull-up transistor and a nitrogen concentration of the interface film of the pull-down transistor. 
 
     
     
       4. The semiconductor device comprising:
 at least one SRAM cell, 
 wherein the SRAM cell includes a pull-up transistor, a pull-down transistor, and a pass-gate transistor, and 
 an inversion-layer thickness (Tinv) of a gate stack of the pass-gate transistor is different from Tinv of a gate stack of the pull-up transistor and Tinv of a gate stack of the pull-down transistor, and 
 wherein a gate electrode of each of the transistors comprises a first metal electrode formed on the gate insulating film and a second metal electrode formed on the first metal electrode, and 
 a thickness of the second metal electrode of the pass-gate transistor is different from a thickness of the second metal electrode of the pull-up transistor and a thickness of the second metal electrode of the pull-down transistor. 
 
     
     
       5. The semiconductor device of  claim 4 , wherein the first metal electrode of each of the transistors comprises LaO, Y2O3, Lu2O3, SrO, or a combination thereof. 
     
     
       6. The semiconductor device of  claim 4 , wherein the second metal electrode of each of the transistors comprises TiN, TaN, or a combination thereof. 
     
     
       7. A semiconductor device comprising:
 at least one SRAM cell, comprising:
 a pull-up transistor, 
 a pull-down transistor, and 
 a pass-gate transistor, 
 
 wherein a nitrogen concentration of a gate insulating film of the pass-gate transistor is different from a nitrogen concentration of a gate insulating film of the pull-up transistor and a nitrogen concentration of a gate insulating film of the pull-down transistor. 
 
     
     
       8. The semiconductor device of  claim 7 , wherein the gate insulating film of each of the transistors comprises a high-k material. 
     
     
       9. The semiconductor device of  claim 7 , wherein:
 an interface film is formed between a substrate and the gate insulating film of each of the transistors, and 
 a nitrogen concentration of the interface film of the pass-gate transistor is different from a nitrogen concentration of the interface film of the pull-up transistor and a nitrogen concentration of the interface film of the pull-down transistor. 
 
     
     
       10. The semiconductor device of  claim 7 , wherein:
 a gate electrode of each of the transistors includes a first metal electrode formed on a gate insulating film and a second metal electrode formed on the first metal electrode, and 
 a thickness of the second metal electrode of the pass-gate transistor is different from a thickness of the second metal electrode of the pull-up transistor and a thickness of the second metal electrode of the pull-down transistor. 
 
     
     
       11. The semiconductor device of  claim 10 , wherein the first metal electrode of each of the transistors comprises LaO, Y2O3, Lu2O3, SrO, or a combination thereof. 
     
     
       12. The semiconductor device of  claim 10 , wherein the second metal electrode of each of the transistors comprises TiN, TaN, or a combination thereof. 
     
     
       13. The semiconductor device of  claim 7 , wherein an inversion-layer thickness (Tinv) of a gate stack of the pass-gate transistor is different from a Tinv of a gate stack of the pull-up transistor and Tinv of a gate stack of the pull-down transistor. 
     
     
       14. An electronic system comprising a semiconductor device, including:
 at least one SRAM device comprising:
 a pull-up transistor, 
 a pull-down transistor, and 
 a pass-gate transistor, wherein the nitrogen characteristics of the pass-gae transistor are different from nitrogen characteristics of the pull-up transistor and pull-down transistor; 
 
 a controller; 
 an input/output (I/O) device; 
 an interface; and 
 a bus configured to interconnect one or more of the controller, the I/O device, and the interface. 
 
     
     
       15. The system of  claim 14 , wherein a nitrogen concentration of a gate insulating film of the pass-gate transistor is different from a nitrogen concentration of a gate insulating film of the pull-up transistor and a nitrogen concentration of a gate insulating film of the pull-down transistor. 
     
     
       16. The system of  claim 14 , wherein the gate insulating film of each of the transistors comprises a high-k material. 
     
     
       17. The system of  claim 14 , wherein:
 an interface film is formed between a substrate and the gate insulating film of each of the transistors, and 
 a nitrogen concentration of the interface film of the pass-gate transistor is different from a nitrogen concentration of the interface film of the pull-up transistor and a nitrogen concentration of the interface film of the pull-down transistor. 
 
     
     
       18. The system of  claim 14 , wherein:
 a gate electrode of each of the transistors includes a first metal electrode formed on a gate insulating film and a second metal electrode formed on the first metal electrode, and 
 a thickness of the second metal electrode of the pass-gate transistor is different from a thickness of the second metal electrode of the pull-up transistor and a thickness of the second metal electrode of the pull-down transistor. 
 
     
     
       19. The system of  claim 14 , wherein an inversion-layer thickness (Tinv) of a gate stack of the pass-gate transistor is different from a Tinv of a gate stack of the pull-up transistor and Tinv of a gate stack of the pull-down transistor.